NEW YORK -- The New York Mets and St. Louis Cardinals are both trying to convince themselves they are still in the playoff race. By Thursday night, the task likely will have become much harder for at least one of the teams.

The Mets and Cardinals will look to keep their flickering postseason hopes alive -- and extinguish the other's chances for good -- during a four-game series at Citi Field that begins Monday night. In the opener, New York's Zack Wheeler (3-6, 4.86 ERA) is scheduled to oppose St. Louis' Adam Wainwright (10-5, 5.20) in a matchup of right-handers.

Both teams are coming off disheartening losses Sunday. The host Mets were routed by the Colorado Rockies 13-4, while the visiting Cardinals gave up two runs in the ninth inning to fall to the Pittsburgh Pirates 4-3.

The lopsided loss for the Mets (41-48) cost them a chance to sweep a three-game series from the Rockies and move within 7 1/2 games of Colorado, which leads the race for the second National League wild card.

"It's just not the way you write it up," said New York left-hander Steven Matz, who took the loss after allowing seven runs in one-plus innings in the shortest start of his career.

Afterward, the Mets took solace in winning the series, even though their big deficit in the wild-card race -- they are now 9 1/2 games behind the Rockies -- all but demands stringing together some sweeps.

"It's all about getting series," New York outfielder Curtis Granderson said. "The big thing is to try to come in, no matter who the opponent happens to be (and) what's going on, and put ourselves in a situation to be able to be victorious. And that's what we were able to do over this first three games back during the second half. Obviously, it doesn't get any easier with St. Louis coming into town."

The Cardinals (44-47) missed an opportunity to win the three-game series from the Pirates when Brett Cecil -- pitching the ninth inning in a save situation for the first time this season -- gave up two runs on three hits, including Adam Frazier's walk-off RBI single.

"(Cecil) has been extremely good lately, and that's why we had him in that situation," St. Louis manager Mike Matheny said. "But those one-run ninths are hard anywhere."

The defeat left the Cardinals 6 1/2 games behind the first-place Milwaukee Brewers in the NL Central and 7 1/2 games behind the Rockies.

"Not something I go looking for," Matheny said before Sunday's game, referring to the division and wild-card standings. "Same old, same old. Just play good baseball."

Wheeler and Wainwright are opposing each other for the second straight start. Wainwright earned the win and Wheeler took the loss in the Cardinals' 4-1 victory at Busch Stadium on July 8. Wainwright allowed one run over 6 2/3 innings, while Wheeler gave up two runs over six innings.

This will be Wheeler's second career start against the Cardinals. Wainwright is 4-5 with a 4.66 ERA in 12 career appearances (10 starts) against the Mets.